PROCESS FOR THE PREPARATION OF beta -HALOGENO-ALKYL-ISOCYANATES

ABSTRACT

N-halogeno-alkyl- Beta -lactams are rearranged into Beta halogeno-alkyl-isocyanates by contacting them with unsaturated organic compounds, optionally under irradiation. The products are highly reactive and useful for the synthesis of heterocyclic compounds.

United States Patent [1 1 Kampe [4 1 Feb. .20, 1973 [54] PROCESS FOR THEPREPARATION OF [58] Field of Search..204/l58 R, 158 HE, 162 R, 162B-HALOGENO-ALKYL-ISOCYANATES HE; 260/453 A, 453 AR, 453 AL, 453 P, 488 F[75] Inventor: Klaus-D eter Kampe, Frank- [56] References Cited furt/Mam, Germany [73] Assignee: Farbwerke Hoechst Aktien- UNITED STATESPATENTS gesellschl" vormals r Lucius 3,401,106 9/1968 Rehovoth et 3|..204/l62 R & Bruning, Frankfurt (Main), Ger- 3,437,680 4/1969 Farrisseyetal ..260/453 A many Primary Examiner-Howard S. Williams [22] Flled'June 1970 AttorneyCurtis, Morris and Safford [21] App]. No.: 43,937

[57] ABSTRACT [30] Foreign Application Priority DataN-halogeno-alkyl-B-lactams are rearranged into B-halogeno-alkyl-isocyanates by contacting them with June 14, 1969 Germany..P 19 30 329.8 unsaturated organic compounds, optionally underradiation. The products are highly reactive and useful [52] 204/158204/162 for the synthesis of heterocyclic compounds.

204/162 HE, 260/453 A, 260/453 P, 260/488 F Int. Cl ..B0lj l/l0, C070119/04 14 Claims, No Drawings PROCESS FOR THE PREPARATION OF B-HALOGENOALKYL-ISOCYANATES The present invention relates to a process forpreparing [3halogeno-alkyl-isocyanates by a rearrangement ofN-halogeno-B-lactams in the presence of a C--C unsaturated compound.

Rearrangement reactions of N-halogeno-B-lactams yieldingB-halogeno-isocyanates in the presence of C- C unsaturated compounds andof catalytical amounts of substances which disintegrate easily intoradicals are already known from Tetrahedron Letters, 1969, pages117-120. In this case, the starting B-lactam is optionally substitutedby radicals which are inert towards the isocyanate group and are linkedto the B-lactam ring via a carbon atom.

It has now been found that B-halogeno-alkyl-isocyanates of the generalformula in which X stands for bromine or chlorine, R and R each standsfor hydrogen or halogen or lower alkyl and R for hydrogen or loweralkyl, and R stands for hydrogen or an aliphatic radical having up to 22carbon atoms, preferably up to carbon atoms, a cycloaliphatic radicalhaving four to eight, preferably five to eight, carbon atoms, anaromatic radical, lower acyloxy, lower carbalkoxy or, if R and/or R eachstands for halogen, for lower alkoxy, and in which two of the radicalsR, R, R and R may form part of a cycloaliphatic or heterocyclic ring orring system, can be prepared from N-halogeno-B-lactams by contactingN-halogeno-B-lactams of the general formula II in which X, R, R, R and Rare defined as above, with an olefin and/or an acetylene at temperaturesof from 200 to +250 C in the absence of substances which disintegrateeasily thermally into radicals under the conditions given above.

According to the invention, the easily reacting brominated compounds arepreferably used.

The rearrangement reaction of the N-halogeno-B- lactams isadvantageously carried out in the presence dicated temperature range;or, in order to shorten the reaction time at temperatures below 60 C, N-

halogeno-B-lactams of the general formula ll are exposed to light of awave length below 700 nm, preferably of from 240 nm to 590 nm, moreparticularly of from 300 nm to 590 nm, or to high-energy irradiation attemperatures of from 200 to +250 C, preferably from about to about +l00C, in the presence of an olefin and/or an acetylene, optionally with theuse of an inert solvent.

The N-halogeno-B-lactams of the general formula II, used as startingmaterials, are prepared according to methods known for theN-halogenation of lactams (cf. for example, B. Taub and J. B. Hino, J.Org. Chem. 25 (1960), page 263; G. Caprara et al., Ann. Chimica 49(1959), page 1167) by halogenation, especially bromination, of thecorresponding B-lactams with the equivalent amount of halogen in thepresence of a sodium hydrogencarbonate solution or dilute sodiumcarbonate solution. The so-obtained impure N-halogeno- B-lactams may beused for the rearrangement reaction of the invention.

The process of the invention is applicable to all compounds containing aB-lactam ring and carrying a bromine or chlorine atom at the nitrogenatom of the lactam group, except B-lactams containing in the moleculegroups which would react with the isocyanate group formed during therearrangement, for example hydroxy or amino groups.

To specify the B-lactams suitable for this process, in I which two ofthe above-mentioned radicals R, R, R and R may form part of rings orring systems, the following B-lactams of the formulas III to VIII may becited as examples, but they are not intended to limit the B-l'actams ofthis type to be used as starting material thereto.

(VIII) Furthermore, dilactams, eg those of the following formulas IX andX, may also be used:

lhC CH:

The B-lactams used as starting products may be prepared by knownmethods, for example from the corresponding olefins and chlorosulfonylisocyanate (N- carbonyl-sulfamic acid chloride) (of. R.Graf, Angew.Chem. 80 (l968),page 179 et sequ.,especially pages 183 to 185; Angew.Chem. Int. Ed. 7 (1968), page 172 et sequ.). Hence, the olefins usedare, above all, 01,01- disubstituted, a, a, B-trisubstituted andtetrasubstituted monoenes and aromatically substituted olefins of thestyrene type. Furthermore, suitable compounds are, especially, bicyclicand polycyclic monoand polyenes as well as allenes. It is also possibleto start from a-substituted and a, B-disubstituted monoenes.Heterocyclic compounds, such as 2-isopropenyl-tetrahydrofuran,2,5-dihydrofuran, 7-oxabicyclo-( 2,2,1 )-heptadiene- (2,5) or7-oxabicyclo-(2,2,l )-hepta-2-ene-5, 6-bis-carboxylic acid methyl esteror 3,4-dialkyl-2, dihydrothiophene dioxide (sulfolenes) are alsosuitable.

B-Lactams carrying carbalkoxy groups can be prepared by oxidation ofalkenyl-substituted B-lactams by means of known oxidizing agentssuitable for the oxidation of olefinic double bonds to yield thecorresponding carboxylic acids and by esterification thereof, forexample with diazo-alkanes.

4-Acyloxy-azetidin-2-ones are obtained from chlorosulfonyl isocyanate(N-carbonyl-sulfamic acid chloride) and the corresponding vinyl esters.

Among the 4-alkoxy-B-lactams that can be used as starting material onlythose are hitherto known which carry one or two halogen atoms in the3-position. They can be obtained from the corresponding N-aryl-B-lactamsprepared by condensation of Schiffs bases with halogenated ketenes byoxidative elimination of the aryl group.

Surprisingly, the rearrangement reaction of the invention is alsoapplicable to optically active N- halogeno-B-lactams. The opticallyactive starting products can, for example be obtained by converting theasymmetrical azetidinone by means of an alcoholic hydrogen chloridesolution and benzaldehyde into the corresponding N-benzal-propionic acidester which is hydrogenated to yield the corresponding 3-benzylamino-propionic acid ester. This ester can be split by means of anoptically active acid, for example tartaric acid, into the enantiomericsalts, from which the pure enantiomers of B-benzylaminmpropionic acidester are set free using bases. These can be converted in known mannerby means of a Grignard compound into the N-benzyl-B-lactams from whichthe benzyl group is split off by means of sodium in liquid ammonia.

[3-Lactams which are especially advantageous for the present inventionare, for example, N-brominated derivatives of 4-alkyl-,4-(monochloroalkyl), 4- (monobromoalkyl)-, 3,4-dialkyl-, 4,4-dialkyl-,4-alkyl- 4-(monochloroalkyl)-azetidinones-(2), the alkyl groups of whichcontain preferably from 1 to 4 carbon atoms, as well as of4-vinyl-azetidinone-(2) and the compounds of the formulas Illa, lllb,lIIc, 1V and VII and 4-acetoxy-azetidinone-(2).

As unsaturated compounds which are necessary for the rearrangementaccording to the invention there may generally be used all olefinsand/or acetylenes which contain one or several C=C double bonds and/or CE C triple bonds but no functional groups that would react with theisocyanate group, advantageously alkenes, alkane-dienes, alkynes,halogenated alkenes, vinyl esters and/or vinyl ethers which boil atnormal pressure below 150 C, preferably between about 25 and about 120C. Especially used are olefins of a simple structure which can beobtained without great technical effort, for example ethylene,acetylene, propene, butene-(l), butene-(Z), 4-methyl-pentene (1),styrene, phenyl-acetylene, butadiene, isoprene, allyl chloride, allylbromide, methallyl chloride, vinyl chloride, vinylethyl ether or vinylacetate or mixtures of these unsaturated compounds, since they can beseparated from the isocyanates -optionally together with a solvent byfractionated distillation at relatively low temperatures which aresubstantially lower than the boiling points of the isocyanates formed.

Even when added in an amount of about 0.01 mol per mol ofN-halogeno-B-lactam the unsaturated compound used has a distinct effect.Generally, the olefins and/or acetylenes are added in an amount of fromabout 0.02 to about 6 mols per mol of N-halogeno-B- lactam. 1 xc cordingto a preferred embodiment of this process, the C-C unsaturated componentis used in about 0.6 to about 8 parts by weight per part by weight ofN-halogeno-azetidinone-(2), the unsaturated component serving at thesame time as a solvent. Suitable olefins for this embodiment are,preferably, those which boil between 30 and about C, for example allyland methallyl chloride, 4-methyl-l-pentene, isoprene, cycloalkeneshaving 5 and 6 carbon atoms, and/or allyl esters of lower aliphaticcarboxylic acids, for example allyl acetate.

The speed of the rearrangement reaction increases when the temperatureis raised and it is proportional to the amount of olefin and/oracetylene in the reaction mixture. The reaction speed is furthermorevery much influenced by the structure of the olefins and acetylenes.

In addition to the above influences, the rearrangement speed may alsoconsiderably be increased by exposing mixtures of N-bromoorN-chloro-B-lactams and olefins and/or acetylenes to light of a wavelength below 700 nm, preferably between 210 and 590 nm, or tohigh-energy irradiation, for example gamma-rays, X- rays or corpuscularrays, such as accelerated electrons. Under the action of these rays therearrangement reaction is almost complete within some hours even at lowtemperatures, for example down to -200 C under the action of gamma-rays.The higher the energy of the rays the lower the temperatures requiredfor the rearrangement reaction. Table I shows different reactionconditions and results obtained from rearrangements ofN-bromo-B-lactams.

TABLE I N'bromo-B-lactam R R Reac- Yield of (5- l Reaction tionbrorno-alkyD- R C-CR G=Cunsaturated temperatime Solvent (in ml.isocyanate in l I compound in mol per I I ture in per mol of percent ofBr-NC= rnol ot fl-lactam Type of irradiation in C. hours fi-lactam) thetheory R R R =H, R =CH Methallyl chloride, 1.0 66 2.5 CHCl 500 92 R R=H, R R =CH3.- Allyl chloride, 1.0 +6l 62 1.5 CHC1ZE500; 90 R R ==H, R R=CH Methallyl chloride, 1.0... +46 2.5 CH2C12(500) 95 R R =H, R RfiCHahAllyl chloride, 0.1 +120 1.5 90 R li -CH3, R R =H.. Methallyl chloride,1.0-.- +83 0.25 Cl-C2H4-Cl (500) 89 R1-R3=(CH2)3, R R -H Methallylchloride, 3.0... 20-22 15 80 R R =(CH2) -R R =H. ...do 0-1 60 15 R R RH, R CHamnun Allyl chloride, 1.0 Wollramtitncandesee 62-64 1. CHC13(500)87 100 we 5. R R R =H, R =CH;.. ..do Osram-Vitalux incandescent 43 0.3CHzClz(300) 89 GUR 53, 300-watt lamp. R Rz=CH R R ==H. do 45 0.1CHzClz(500) 91 R Ra=CH R R =H. 53 91 R R =CH;, R R =H 'de .d 77 88 R R,:CH3, R R=H 38-40 90 B R =CH;, R R =H -methyl-l-pentene, 56 1. 3 R ,R=CH ,R .R =H. Methallyl chloride, 6.0.. ram talux incandescent 46 3. 92

lamp, GUR 53 300 watts. R ,R==CH ,R ,R =H Isobutene, 4.0 do -10 1.50112012080) 90 R ,R =CH3,R ,R =H Methallyl chloride, 1.0ctilgaltioo-irrp/rtiliator, dose rate -45 3.0 CHzCl (500) 88 X 0 ra R ,R=CH;,R ,R =H 0 74 3.0 CH Cl 500 0 R ,R=' =CH;,R ,R =H.Cobalt-GO-irradiator, dose rate 193 6.0 5- 8 2.2) 10 rad/h. R1,RbCH,R2,R4=H Allyl chloride, 0.6 Cgbalg od-iirlrkadiator, dose rate 44 2.0CHQClz (500) 90 X1 ra R ,R =H,R ,R =CH ctlibaltl-fidirgalgiator, doserate 61 0.25 CHCI; (500) 94 .5X 0 re R ,R,R H,R =CH Isoprene, 1.0 Cobasltigp-irizplttiliaton dose rate 44 3.0 CHzClz(500) 80 4.5 ra R R R -H, R=CHCHZ4(R) 4-methyl1-pentene, 2.0.. Cobalt-tiO-irradiator, dose rate0 1. 5 01 1201 050 81 '(+)-enant1omer. 1.5X10 rad/h.

R ,R =(CH )o-R ,R =H. Isobutene, 3.0 Cobalt-GO-irraditor, dose rate 2.0CHZC12(150) 82 1.5X10 rad/h.

1 The yields are calculated on B -lactarn as a starting material, hencethey comprise both steps: the preparation of N-bromo-lactam and therearrange ment reaction.

2 Without irradiation under exclusion of light.

3 A mixture of isobutene and N-bromo-lactam was irradiated in the solidstate. The yield was evaluated with the aid of an infrared spectrum ofthe crude reaction product.

When light is chosen for irradiation, all light sources, including daylight, are generally suitable as far as they emit light of the wavelength mentioned. Light of a wave length of from 300 to 590 nm ispreferably used according to the invention. Thus, the irradiationsources used are conventional tungsten incandescent lamps, especiallydaylight incandescent lamps, for example Osram Ultra-vitalux lampsand/or day light. The rays may pass through usual apparatus glass, thussimplifying very much an industrial-scale operation of the process. Asirradiation sources there may, of course, also be used mercury burnersboth as external irradiation sources and in the form of immersion lampsprovided with a quartz jacket. When the irradiation sources chosen emitso-called high-energy rays, the speed at which the rearrangement of theinvention takes place is still sufficiently high fos an industrialscaleoperation even at temperatures below C. Table I also shows the yields ofisocyanates obtained by the rearrangement at low temperatures under theaction of gamma-rays produced by a cobalt-60 source. The evidence thatthe rearrangement actually takes place at low temperatures (less than 40C) and not as a result of the isolation of the reaction products wasestablished, inter alia, in the following manner: The rearrangement wascarried out in methyl chloride solution in the presence of isobutyleneat -65 C with exposure to gamma-rays for 4 hours. Methyl chloride andapplied. corresponding N-bromo-fl-lactam yields,

within 3 hours, an amount of isocyanate below 4 percent of the theoryonly. Moreover, it appeared that an at least percent-rearrangement ofN-bromo-B-lactams at temperatures between 1 0 and +10C requires areaction time of more than 20 hours with the addition of methallylchloride of up to 1 mol per mol of N- bromo-lactam, when the reaction iscarried out without irradiation (including light). Table l furthermoredemonstrates that the reaction time can be reduced to r a few minutes ata temperature between 40 and 60 C under the action of light orhigh-energy irradiation.

The smooth, though slow, course of the rearrangement reaction attemperatures below 25 C without irradiation is very surprising.Alternatively, the smooth course of the rearrangement under the actionof the above-mentioned rays is also surprising since it is known thatN-halogeno-amides and N-halogenourethanes add very easily to C=C-doublebonds under these conditions (cf. DAS l 271 704, K. Schrage, TetrahedronLetters 1966, p. 5795, K. Schrage, Tetrahedron Letters 1967, p. 3033).The strong tendency of N-bromo-amides to add to C=C-double bonds hasalso been disclosed by Z. Foldi, Chem. Ber. 63, p.225? (1930). Accordingto the process of the invention, however, the(B-bromo-alkyl)-isocyanates are obtained in a yield exceeding percent,in the presence of olefins and/or acetylenes, and even in an excess ofan olefin that is liquid under the reaction conditions, with exposure toultraviolet light as well as under the action of gamma-rays, i.e. underconditions under which the above-mentioned addition reactions ofN-halogeno- 65 amides to double bonds take place. In spite of the knowntendency of N-bromoand N-chloro-B-lactams to rearrange into(B-halogeno-alkyl)-isocyanates under the action of radical-formingcatalysts, it could not be expected that addition reactions, especiallyof N- bromo-B-lactams to C=C-double bonds, would take place to a verylimited extent only, or would not take place at all, under theconditions of the invention, especially with irradiation. If theaddition reactions mentioned above and known from the literature tookplace owing to the thermal treatment and/or irradiation, the proportionof N-halogeno-B-lactams reacting in this manner would be lost for theyield of halogeno-alkylisocyanates. The good yields of(B-bromo-alkylyisocyanates obtained according to the invention provethat the rearrangement reaction proceeds obviously quicker than theaddition reaction.

It has been found that N-(B-bromo-alkyl)-B-lactams of the formula X1 donot rearrange into isocyanates under the conditions of the presentinvention. 1

Furthermore, it is known that isocyanates polymerize and co-polimerizewith compounds capable of polymerization under the action of gamma-rays(cf. C.A. 62 (1965) 642e, J. Fac. Eng. Univ. Tokyo 1, p. 46 (1936)published Japanese Patent application Nos. 15,932 (1962), filed Oct. 6,1960, and 17,695 (1962),filed Oct. 29, 1960).

It has, moreover, been taught that alkyl-isocyanates are altered bydecomposition reactions under the under of ultraviolet light attemperatures of from 20 to 100 C. Such an alteration is disclosed, forexample, in J. Amer. Chem. Soc. 79, p. 2533 (1957). When the process ofthe invention is carried out with exposure to ultraviolet light, veryshort irradiation times (from 2 to 20 minutes) are already sufficient toachieve an almost complete rearrangement. Over such a short irradiationtime, the (B-halogeno-alkyl)-isocyanates of formula I are obviously notaltered to an appreciable extent, as the good yields demonstrate in thecase of X being bromine. Appreciable amounts of decomposition productsare obtained according to the invention only if N-chloro-B-lactams, andespecially N-bromo-B-lactams, are exposed to light from mercury vaporburners in the form of quartz-jacket immersion lamps for more than 1hour or to light from mercury vapor lamps through apparatus glass formore than 5 hours at a temperature exceeding 35 C.

By-products that would be formed under the reaction conditions of theinvention in a manner similar to the cited addition reactions and/orowing to subsequent alterations of the isocyanates obtained would, inthe first line, not only reduce the conversion rate into isocyanates butwould also decisively aggravate the separation of the(B-halogeno-alkyl)-isocyanates by distillation. Compared with theprocess proposed in Tetrahedron Letters 1969, pages 117-120, the processof the invention shows various substantial advantages. Since no chemicalcompounds are incorporated as radical-forming agents which would causeformation of undesired by-products either in the form of theirdecomposition products or of compounds obtained by reactions of thesedecomposition products with the isocyanates, there are no residuesresulting therefrom to have a disadvantageous effect on the isolation ofthe products of the invention, especially of(B-bromo-alkyl)-isocyanates. The working up, especially thedistillation, of the B-chloroand B-bromo-alkyl-isocyanates formed issimpler and leaves substantially less residues. To achieve a comparablerearrangement speed as reached under the exposure to light or uponboiling of the N-bromo-B-lactams in an excess of olefins and/oracetylenes boiling between 30 and C, the known process requiresrelatively high amounts (more than 0.2 mol-percent of radical-formingcatalysts which necessarily reduce the yield and increase the amount ofthe residues mentioned. In the course of the rearrange ment reaction inthe presence of radical-forming catalysts undesired by-products are alsoformed by a more or less intense polymerization or telomerization of theolefins and/or acetylenes used as additives. According to the process ofthe present invention, such polymerizations or telomerizations do nottake place to an appreciable extent. Owing to the fact that the processof the invention requires only readily volatile CC-unsaturated compoundsin addition to the starting material for the preparation of isocyanatesof the formula 1 and therefore only yields very small amounts ofsparingly volatile or non volatile by-products, the process of thepresent invention can easily be carried out in a continuous manner.

The said advantages contribute to the fact that the(B-bromo-alkyl)-isocyanates of the invention are easily obtained in ayield of from 84 to 95 percent of the theory. Thus, especially thespace-time yields are distinctly higher than those obtained by theprocess proposed in Tetrahedron Letters 1969, page 117. In the case ofthe corresponding chlorinated compounds the yield is substantiallylower, generally below 40 percent of the theory.

The preparation of the isocyanates according to the invention can verysimply be carried out on an industrial scale. A mixture consistingpredominantly of impure N-bromoor N-chloro-fi-lactam and an olefinand/or acetylene, is allowed to stand over a period which is sufficientfor a complete rearrangement reaction, optionally in the presence of aninert solvent. To accelerate the reaction the mixture is either heatedto a temperature of from 30 to C or heated to a temperature above 20 Cwhile exposing it to light or to a high-energy irradiation at atemperature which preferably exceeds -40 C and, optionally heating it.Subsequently, the reaction mixture is subjected to a fractionateddistillation in vacuo.

The process of the invention which, in comparison to the known synthesesof isocyanates, can very simple be carried out in practice for thepreparation of isocyanates of the formula 1 differs in principle fromthe methods hitherto proposed.

Compared with the process known 7 from Tetrahedron Letters, loc. cit.,the novel simplified and improved process of the invention for therearrangement of N-bromoand N-chloroazetidinones-(2) has a very widescope of application. According to this process, a great variety ofisocyanates which hitherto have been very difficult to prepare or havenot at all been obtainable can now be prepared in a simple manner and ina single reaction step.

In addition to the great number of possible modifications obtained withthe isocyanate group, the compounds prepared according to the inventionpermit some further possible reactions for a synthesis, due to thebromine or chlorine atom linked in the B-position to the isocyanategroup. Therefore, the (B-bromoand B-chloro-alkyl)-isocyanates obtainedaccording to the invention are valuable intermediates suitable for avariety of applications, for example in the manufacture of pesticides orplastic materials.

The new a-acyloxy-B-halogenoalkyl isocyanates are especially usefulintermediate products for organic syntheses, in as much as thosenotoriously reactive groups the isocyanate, the acyloxy and anahalogenoalkyl group are bound to one carbon atom. If the isocyanategroup is transformed into the amino group by known hydrolysis anddecarboxylation, a N- Oacetal moiety is obtained, Le. a derivative of ahighly reactive halogeno-acetaldehyde.

The a-acyloxy-fl-bro mo isocyanates react in known manner with dialkylamines to yield 2-dialkyl-amino-4- acetoxy-2-oxazolines, which can behydrolyzed and subsequently oxydized to the corresponding4-oxocompounds, which are known central stimulants and have anorexticproperties (J. Org. Chem. 27 (1962) 1679-1685).

The following examples serve to illustrate the invention.

EXAMPLEl a. Preparation of N-bromo-4-methyl-azetidinone- (2): 160 g ofbromine were added dropwise while vigorously stirring at roomtemperature within 30 minutes to a mixture of 85 g (1 mol) of4-methylazetidinone-(Z), 120 g (1.45 mols) of sodium bicarbonate, 500 mlof methylene chloride and 300 ml of water, and stirring was continuedfor to 20 minutes until the reaction mixture had a faintly yellow color.The mixture was then suction-filtered, the filter residue was washedwith a small amount of methylene chloride, the phases of the filtratewere separated and the aqueous phase was shaken once or twice withmethylene chloride. The methylene chloride extracts were united with thecorresponding phase of the filtrate of the reaction mixture, thesolution was then dried over sodium sulfate, filtered off and evaporatedin vacuo at a bath temperature of 37 40 C by means of a rotatoryevaporator. The residue consisted of from 162 to 168 g of crudeN-bromo-4-methyl-azetidinone-(2) in the form of a viscous oil having afaintly yellow-brown color. This product was used without furtherpurification as the starting material for the rearrangement reaction.

b. Rearrangement of N-bromo-4-methylazetidinone-(Z): A mixture of 162168 g of crude N- bromo-4-methylazetidinone-(2) as obtained after theaforementioned bromination of 1 mol of 4-methyl-2- azetidinone, 500 mlof chloroform and 90.5 g 99 ml A 1 mol) of methallyl chloride wasrefluxed for 2.5 hours. Subsequently, the low-boiling solvent and theolefin were first distilled off in vacuo and then(B-bromo-isopropyl)-isocyanate formed was isolated by fractionateddistillation of the crude reaction product. Boiling point: 57.8 C, undera pressure of 14 torr; n 1.4712; yield: 151 g 92 percent of the theory.This yield and the yields cited in the following examples of(B-bromo-alkyl)-isocyanates are calculated on the starting fi-lactamused for the N-bromination, i.e., on both steps.

EXAMPLEZ When the rearrangement reaction disclosed in Example sub b wascarried out by refluxing for 3 hours under the exclusion of light, 141 g(86 percent of the theory) of pure (B-bromo-isopropyl)-isocyanate wereobtained after distillation.

EXAMPLE3 A mixture of 166 g of crude N-bromo-4-methylazetidinone-(Z)prepared according to Example 1 a, 500 ml of methylene chloride and 99ml (1 mol) of methallyl chloride was refluxed for 3 hours under theexclusion of light. After fractionated distillation in 313556748 percentof the theory) of pure (B- bromo-isopropyl)-isocyanate were isolated.

EXAMPLE4 A mixture of 81 g (0.5 mol) of crude N-bromo-4-methyl-azetidinone-(2) and 5 ml (0.05 mol) of methallyl chloride washeated to 90 C under the exclusion of light. Subsequently, thetemperature rose suddenly to 116 C. The reaction mixture was maintainedat this temperature for 15 minutes and then subjected to fractionateddistillation in vacuo. In addition to a considerable amount ofdistillation residue, 35 g (43percent of the theory) of pure(fi-bromo-isopropyh-isocyanate were obtained.

EXAMPLES A mixture of 164 g of crude N-bromo-4-methylazetidinone-(Z),200 ml of 1,2-dichloro-ethane and 99 ml (1 mol) of methallyl chloridewas heated to 90 C for 12 minutes under the exclusion of light. Afterfractionated distillation in vacuo 143 g 87 percent of the theory) ofpure (B-bromo-isopropyl)-isocyanate were obtained.

EXAMPLE6 A mixture of 179 g of crude N-bromo-4,4-dimethylazetidinone-(2) prepared in the same manner as disclosed inExample 1 a, 500 ml of chloroform and 81 ml (1 mol) of allyl chloridewas refluxed for 1.5 hours under the exclusion of light. Subsequentlythe reaction mixture was subjected to fractionated distillation invacuo. The (fl-bromo-tertiary-butyl)-isocyanate formed boiled at 51.3 Cunder a pressure of 10 torr; n 1.4633. The yield of isocyanate was g (90percent of the theory).

EXAMPLE7 The same mixture as disclosed in Example 6 was refluxed for 1.3hours at day-light. After fractionated distillation in vacuo 163 g (92percent of the theory) of pure (B-bromo-tertiary-butyl)-isocyanate wereobtained.

EXAMPLES8tol2 Rearrangement of N-bromo-4, 4-dimethylazeti'dinone-(Z)under the exclusion of light; the reaction and isolation of(B-bromo-tertiary-butyl)-isocyanate were carried out as disclosed inExample 6.

TABLE 2 Mol of M01 oi Yield of allyl methallyl Internal isocyanate M0101 chlorlile/ chloride/ tempera- Reaction in percent N-hromomol 01 molof ture in time the Example laotum fl-loetam fl-laetam Solventin ml. C.in hours theory 8 1.0 0.5 (lUCl;t(500).." 61-62 1.5 88 !l 1.0 0.. (11101(50) 85 2.0 73 1.0 1.0 Cll1( l (500).. 42-44 2.5 58 ll 1.0 0.1 120 1.5ill) 12,. 1.0 1.0 (111 01 (500).. 4540 2.5 95

1O E X A M P L E S to 97 g (1 mol) of 4-vmyl-azetidmone-(2), 600 ml ofRearrangement f N bromo 3, 4 dimethy1 carbon tetrachloride and 178 g (1mol) of N-bromoazetidinone-(2) under exclusion of light; reaction andisolation corresponding to Table 2; (B-bromo-isobutyl)-isocyanate wasformed.

succinimide were mixed, 10 mg of dibenzoyl peroxide were added and themixture was heated to 43-47 C. When the reaction was complete, 150 ml ofhexane TABLE 3 M01 of M01 of Yield of allyl methallyl Internalisocyanate M01 01 ehloride/ chloride] tempera- Reaction in percentN-bromomol of mol of ture in time of the lactarn fl-lactam fl-lactamSolvent in ml. C. in hours theory 1.0 1.0 CH2Cl: (500)... 42-44 3.089 1. 1. 0 CHC13(500)... 61-62 2.0 87 1. 0 0.6 CHC13(400) 02 2.0 850. 1. 0 C1.CH4Cl 33 0.25 89 (250). 0. 5 0. 1 6112012 (250). 44 3.0 540.5 0.2 Cl-CzHqCl 83 0.5 68

EXAMPLE EXAMPLE21 A mixture of 117 g (0.5 mol) of crude N-bromo-3, 4-hexamethylene-azetidinone-(2) prepared according to Example 1 a and 200ml of cyclo-octene was heated to 90 C for 2 hours under the exclusion oflight. The mixture was then subjected to fractionated distillation invacuo (less than 2 torr). The isocyanate formed boiled at 72-76 C undera pressure of 0.01 torr. 65-73 g 56-63 percent of the theory) of pure(2-bromocyclooctyl)-isocyanate were obtained, n 1.5200.

EXAMPLE22 A mixture of 113 g (0.5 mol) of crude crystallized N-bromo-4-phenyl-azetidinone-(2) obtained according to Example 1 a, 200 mlof chloroform and 75 ml (0.75 mol) of methallyl chloride was refluxedfor 2 hours under the exclusion of light. Subsequently, the chloroformand the methallyl chloride were distilled off under a pressure of 2torr. The viscous oily residue was distilled under greatly reducedpressure by means of a thin-layer evaporator. 95 g 83 percent of thetheory) of (2-bromo-l-phenyl-ethyl)-isocyanate were obtained, boilingpoint 69 72 C under a pressure of 0.01 torr; n 1.5652.

EXAMPLE23 0. Preparation of N-bromo-4-vinyl-azetidinone-(2) were added,the mixture was cooled to 4- 8 C and the undissolved succinimide wasseparated by suction-filtration. The filtrate was evaporated in vacuo.170-180 g of crude viscous oily N-bromo-4-vinyl-azetidinone- (2) wereobtained. This product was used as a starting material for therearrangement reaction.

b. Rearrangement of N-bromo-4-vinyl-azetidinone- A mixture of 174 g (1mol) of crude N-brom0-4- vinyl-azetidinone-(Z), 300 ml of methylenechloride and 99 ml of methallyl chloride (1 mol) was refluxed for 2.5hours. Subsequently, the reaction mixture was subjected to fractionateddistillation in vacuo. 153 g (87 percent of the theory) of pure(2-bromo-l-vinylethy1)-isocyanate were obtained; boiling point 58 Cunder a pressure of 7 torr; n 1.4916.

EXAMPLE24 A mixture of 88 g (0.5 mol) of crude N-bromo-4-vinyl-azetidinone-(Z) prepared according to Example 23 a, 200 ml ofchloroform and 51 g (0.75 mol) of isoprene was refluxed for 3 hoursunder the exclusion of light. Subsequently, the reaction mixture wassubjected to fractionated distillation. 58 g (66 percent of the theory)of pure (2-bromo-l-vinyl-ethyl)-isocyanate were obtained.

EXAMPLE25 A mixture of 214 g (1 mol) of crude N-bromo-4-methyl-4-chloromethyl-azetidinone-(2) prepared according to Example 1 a,350 ml of 1,2-dichloro-ethane and 65 ml (0.8 mol) of allyl chloride washeated to C for 1 hour. Subsequently, the reaction mixture was subjectedto fractionated distillation. g 73 percent of the theory) of pure(fl-bromo-B-chloro-tertiary-butyl) isocyanate were obtained, boilingpoint 40 C under a pressure of 1.6 torr, n 1.4974; analysis calculatedfor C I-l,BrClNO: C 28.26; H 3.32; Br 37.61; Cl 16.68; N 6.59;, found: C28.0; H 3.3; Br 38.2; C1

l7.0; N 6.3; the molecular weight established by mass spectrometry wasalmost the same as that which had been calculated (2l2.5).

EXAMPLE26 40 45 g of propene (about 1 mol) were condensed into a mixturewhich had been cooled to 60 C and which consisted of 166 g of crudeN-bromo-4-methylazetidinone-(2) and 400 ml of l,2-dichloro-ethane. Thismixture was filled in an autoclave of a capacity of 2 liters, at atemperature below 25 C and heated to 90 C for 2 hours under autogenouspressure. Subsequently, the readily volatile constituents of the mixturewere eliminated in vacuo and the residue was distilled in vacuo. 103 g(63 percent of the theory) of pure (B-bromo-isopropyl)-isocyanate wereobtained.

EXAMPLE27 A mixture of 117 g (0.5 mol) of N-bromo-4-methyl-4-carbethoxy-azetidinone-(2), 250 ml of methylene chloride and 50 ml(0.5 mol) of methallyl chloride was refluxed for 2.5 hours. Subsequentlythereaction mixture was subjected to fractionated distillation in vacuo.107 g (91 percent of the theory) of pure(a-carbethoxy-B-bromo-isopropyl)-isocyanate were obtained. Boilingpoint: 7071 C under a pressure of 0.6 torr; n

EXAMPLE28 EXAMPIJE29 a. A mixture of 1 mol of crude N-bromo-3, 4-dimethyl-azetidinone-(Z) and 600 ml (6 mols) of methallyl chloride wasrefluxed for 45 minutes and then subjected to fractionated distillationin vacuo. 157 g 88 percent of the theory) of pure(B-bromo-isobutyl)-isocyanate (threo-erythro mixture) were obtained.

b. A mixture consisting of 0.5 mol of crude (+)-N-bromo-4(R)-vinyl-azetidinone-(2) and prepared according to Example 23 aand 300 ml (3 mols) of methallyl chloride was refluxed for 0.6 hour andthen subjected to fractionated distillation in vacuo. 75 g 85 percent ofthe theory) of pure (S) ()-4-bromo-3- isocyanato-butene-( l) wereobtained; [011 47.1 (c 1.590, methylene chloride); [01],, 73.0 (notdiluted; 1 dm); n 1.4919.

EXAMPLE30 A mixture of 1 mol of crude N-bromo-3,4-dimethylazetidinone-(2) and 400 ml (4 mols) of isoprene was refluxedfor 2 hours and then subjected to fractionated distillation in vacuo.160 g (90 percent of the theory) of pure (fi-bromo-isobutyl)-isocyanate(threo-erythro mixture) were obtained.

EXAMPLE31 A mixture of 1 mol of crude N-bromo-4-methyl-4-chloromethyl-azetidinone-(2) and 400 ml of methallyl chloride wasrefluxed for 1.3 hours and then subjected to fractionated distillationin vacuo. 178 g (84 percent of the theory) of pure(B-bromo-B'-chloro-tertiary-butyl)-isocyanate were obtained.

EXAMPLE32 400 g of N-bromo-4-methyl-{3-lactam were added EXAMPLE33 a. Amixture of 0.5 mol of crude N-bromo-4-methylfi-lactam, 150 ml ofmethylene chloride and 40 ml of allyl chloride was exposed to light froman Osram Vitalux incandescent lamp GUR 53 of 300 Watts for 18 minutes atan internal temperature of 43 C, the reaction mixture then subjected tofractionated distillation in vacuo. 72 g (88 percent of the theory) ofpure (B-bromo-isopropyl)-isocyanate were obtained.

b. A mixture of 0.5 mol (83-84 g) of crude ()-N-bromo-4-(R)-methyl-azetidinone-(2), 250 ml of chloroform and 40 m1 ofallyl chloride was exposed for 1.5 hours to light from a usual Wattincandescent lamp at reflux temperature. The mixture was then worked upin the manner disclosed sub (a). 71 g (87 percent of the theory) of pure(R) ()-(B-bromoisopropyl)-isocyanate were obtained; a 35.l

(not diluted, 1 dm); [011 23-0 (methylene chloride,c= 1.137); n 1.4715.

EXAMPLE34 a. A mixture of 0.5 mol of crude N-bromo-4-methyl-4-chloromethyl-azetidinone-(2), 50 ml of methallyl chloride and 200 mlof methylene chloride was exposed for 2 hours to light from an OsramVitalux incandescent lamp GUR 53 of 300 Watts at reflux temperature andthen subjected to fractionated distillation in vacuo. 87 g (82 percentof the theory) of pure (B- bromo-B'-chloro-tertiary-butyl)-isocyanatewere obtained.

b. A mixture of 0.5 mol of crude N-bromo-4-methyl-4-chloromethyl-azetidinone-(2), 100 ml of methallyl chloride and 200 mlof methyl chloride was exposed for 3 hours to light from a usual200-watt-incandescent lamp at reflux temperature and then subjected tofractionated distillation in vacuo. 82 g (77 percent of the theory) ofpure (B-bromo-B-chloro-tertiary-butyl)-isocyanate were obtained.

EXAMPLE35 A mixture of 0.25 mol of crudeN-bromo-4-n-decylazetidinone-(Z), 200 ml of methylene chloride and 40 mlof allyl chloride was exposed forv 30 minutes to light from an OsramVitalux incandescent lamp GUR 53 of 300 watts at an internal temperatureof 44 C. Subsequently, the low-boiling constituents of the reactionmixture were eliminated in vacuo and the remaining viscous oily residuewas distilled at greatly reduced EXAMPLE36 A mixture of 0.25 mol ofcrude N-bromo-3, 4- dimethylazetidinone-(Z), 125 ml of methylenechloride and 25 ml of methallyl chloride was rapidly heated to 44 Cunder the exclusion of light and then exposed for 6 minutes to lightfrom an Osram Vitalux incandescent lamp GUR 53 of 300 watts.Subsequently, the reaction mixture was rapidly cooled to 3 C andevaporated in vacuo at this temperature. The residue was subjected tofractionated distillation in vacuo. 40.5 g (91 percent of the theory) of(B-bromo-isobutyD-isocyanate were obtained.

When ()-N-bromo-trans-3, 4-dimethylazetidinone-(Z) was used as startingmaterial [11],, 2 70 i 0.3, c 2.00, methylene chloride),2-isocyanato-3-bromo-butane was obtained in the form of a 1 1 mixture ofdiastereomers having a rotation of [a] 2.7 (c 1.48, methylene chloride).

When the mixture was exposed for 30 minutes, instead of in the mannerdisclosed above, to light from a usual 100-watt-incandescent lamp, theyield of isocyanate, after distillation, was 87 percent of the theory.

EXAMPLE37 A mixture prepared at 25 C from 0.25 ml of crude N-bromo-3,4-trimethylene-azetidinone-(2) and 150 ml of methallyl chloride wadexposed while stirring at 46 C for 3 hours to light from the Vitaluxlamp mentioned in Example 36. Subsequently, the methallyl chloride wasevaporated at -15 to 25 C under greatly reduced pressure.

The infrared spectrum of the residue indicated that the N-bromo-lactamwas almost completely rearranged into isocyanate. The crude reactionproduct was distilled in vacuo. 43 g (91 percent of the theory) of pure(2-bromo-cyclopentyl)-isocyanate (cis/trans mixture) were obtained.

EXAMPLE38 A mixture prepared at 25 C from 0.5 mol of crude N-bromo-3,4-hexamethylene-azetidinone-(2), 75 ml of methylene chloride and 84 g(1.5 mol) of isobutene was exposed to light while stirring at 25 C for 2hours as disclosed in Example 36. Subsequently, the low-boilingconstituents of the reaction mixture were evaporated at to 12 C undergreatly reduced pressure. The residue, the infrared spectrum of whichstill contained a very faint lactam-carbonyl band, was distilled invacuo. 185 g (80 percent of the theory) of pure(2-bromo-cyclooctyl)-isocyanate were obtained; boiling point 72 75 Cunder a pressure of 0.01 torr; n 1.5201, The values of C, H, Br and Nobtained by the elementary analysis were almost the same as thecalculated values and the molecular weight determined by massspectrometry corresponded to the calculated value.

EXAMPLE39 A mixture of 0.1 mol of crude N-bromo-4-ethylazetidinone-(2)and 28 g (0.4 mol) of pentine-(l) was refluxed for 5 hours. The mixturewas then subjected to fractionated distillation in vacuo. 14.2 g percentof the theory) of (2-bromo-1-ethyl-ethyl)-isocyanate were obtained.

EXAMPLE4O A mixture of 0.25 mol of crude N-bromo-3-azatricyclo (4.2.1.0.nonanone-(4) and 100 ml of allyl chloride was refluxed for 12 minutesand then subjected to fractionated distillation in vacuo. 50 g (92percent of the theory) of pure2-bromo-3'isocyanatobicyclo-(2.2.1)-heptane were obtained; boiling point50 C under a pressure of 0.2 torr; n 1.5153. The isocyanate showedcorrect analytical values for C H BrNO and the molecular weightdetermined by mass spectrometry corresponded to the calculated value.

EAMPLE41 A mixture of 0.25 mol of crudeN-bromo-4-carbomethoxy-azetidinone-(2) and 84 g (lmol) of4-methylpentene-( 1) was exposed for 24 minutes to light from an OsramVitalux incandescent lamp GUR 53 of 300 watts at reflux temperature.Subsequently, the reaction mixture was subjected to fractionateddistillation in vacuo. After re-distillation, in vacuo, 38 g (73 percentof the theory) of pure (2-bromo-1-carbomethoxyethyl)-isocyanate wereobtained; boiling point 53 C under a pressure of 0.2 torr; n 1.4733;m.p. 29 30 C. The isocyanate showed the correct analytical values for CH BrNO and the calculated molecular weight was determined by massspectrometry.

EXAMPLE42 A mixture prepared at 15 C from 0.5 mol of crudeN-bromo-4methyl-4-n-propyl-azetidinone-(2), 30 ml of methylene chlorideand 1 12 g (2 mols) of isobutene was exposed to light from the lamp usedin Example 41 at 7 C for 1.5 hours. The low-boiling portions of themixture were then evaporated at 5" to 10 C at greatly reduced pressureand the (2-bromo-lmethyl-1- n-propyl-ethyl)isocyanate was distilled invacuo. 93 g (90 percent of the theory) of pure isocyanate were obtained;boiling point 74 C under a pressure of 6 torr; n 1.4680. The analyticalvalues obtained and the molecular weight determined by mass spectrometryconfirmed the constitution C H BrNO.

EXAMPLE43 A mixture of 0.5 mol of crude N-bromo-4, 4-dimethyl-azetidinone-(Z) and 210 g of 4-methyl-pentene-( 1) was refluxedfor 1 hour and then subjected to fractionated distillation in vacuo. g(94 percent of the theory) of pure (fl-bromo-tertiary-butyl)isocyanatewere obtained.

EXAMPLE44 A mixture of 0.5 mol of pureN-chloro-4,4-dimethylazetidinone-(2) and 300 ml (3 mols) of methallylchloride was exposed for 4 hours to light from the lamp used in Example41 at reflux temperature. The reaction mixture was then subjected tofractioned distillation in vacuo. The isocyanate fraction was distilledthree times. Subsequently, 10.7 g (16 percent of the theory) of 92percent (B-chloro-tertiary-butyl)-isocyanate determined by gaschromatography; boiling point 52.5 C under a pressure of 24 torr; n1.4355.

EXAMPLE45 A mixture 33 g (about 0.12 mol) of crude N-bromo- 3,3-dichloro-ethoxy-azetidinone-(2) prepared according to Example 1 a and80 ml of methallyl chloride was 10 exposed for 1 hour to light from anOsram-Vitalux incandescent lamp GUR 53 .of 300 watts at an internaltemperature of from 70 to 73 C. The reaction mixture was then evaporatedin vacuo. The viscous oily residue was dissolved in 50 ml of ether and150 ml of n-hexane were added to the solution. A highly viscoussubstance precipitated which was separated by decanting from thesolution. The solution of ether and hexane was evaporated in vacuo andthe residue (a viscous oil) was EXAMPLE47 A mixture of 0.5 mol of crudeN-bromo-4-methylazetidinone-(2), 250 ml of methylene chloride and 24 ml(0.3 mol) of allyl chloride was exposed for 3.2 hours at refluxtemperature (43-44 C) to gamma rays produced by a cobalt-60 sourcehaving a dose rate of EXAMPLES 50 T 70 [Rearrangement reactions withexposure to gamma-rays produced by a cobalt-60 source] Yield fl-lactambromoor B- R R chloroalkyl R R isooya- Reaction Dose Irradianate inC=C-unsatu.rated Solvent (in ml. temperarate tion percent Examplecompound in moi per mol per mol of ture in time of the o. O of B-lactamfi lactam) 111 C. rad/h. in hours theory Isoprene (1.0) CHCI; (500)59-60 4. 5X10 2.0 87

.. 4-methyl-l-pentene (3. 22 3x10 3. 0 83 62. a, Isobutene (1.0) CHzClz(300).. -8 3X10 1.5 83

53. Same as above Methailyl chloride (1.0).... CH Cl, (300) 45 1. 5X103. 0 88 54. do Methallyl chloride (0.4).... Cl-CzHrCl (500) 8b 4.5)(0.15 01 55 =Br; R R =H; R R =(CH )a Pentine-(l) (1.0) 0 1. 5X10 1. 0 8556 Same as above Allyl acetate (2.0) 1. (5X10 3. 0 84 59 X=Br; R=CH=CH;; R R R =H Cyclohexene (4.0) 1. 5X10 3. 0 81 60 X=Br; R=CH=CH;; RR R =H, 4- 4-methyl-l-pentene (2.0) CHgCh (150) 0 1. 5X10 1.6 81

(R)-(+) enantiomcr. 4

61 X=Br; R B -H; R==CH9; R =CH1CI Allyl chloride (0.5) CHO]; (500) 62 1.5X10 4.0 80

62 X=Br; R R =H; R R =CH Allyl chloride (0.6) CHCla (500) 61 1. 5X10 0.294

63 X=Br; R =OOOCH R R R =H Methaliyl chloride (1.0)..-- CHgClz (160) 444.5Xl0 1.0 78

64 X=Br; R =C H R R R =H Isoprene (2.0) CH C], (300).... 41 1.15X10 2.077

65 o Isoprene (6.0) 22 1. 5x10 2. 0 7

I NBr 66 0 Isoprene (1.0) CH Cl: (300) 0 1.5X10 3.0 86

NBr

67 X=Br; R R =H; R =OH R =OH OL Methallyl chloride (6.0) 40 3X10 0.3 78

68 X=Cl; R =CHs; R R R =H Methallyl chloride (5.0) 30 3X10 15 1 70 X=Br;R R R =H; R =CHaCO0- Isobutene (2.0) OHzClg (600) 25 1.5X10 2 a Physicaldata of: 5is0eyanato-6-bromo-cyclooctene, sis/trans mixture, boilingpoint: 87-88 0.; no: 1.5308. Analytical values and determination ofmolecular weight correspond to CoHizBrNO.

subjected to fractionated distillation at greatly reduced pressure. Afraction which distilled over between and 92 C at a pressure of 0.01torr proved, after determination by gas chromatography, to be an about85 percent-(2.2.2-bromo-dichloro-l-ethoxy-ethyl)-isocyanate which wasobtained in a yield of 18.6 g (50 percent of the theory); n 1.5032.

EXAMPLE46 A mixture of 0.5 mol of crude N-bromo-4-acetoxyazetidinone-(2)prepared at 0 C according to Example 1 a, 400 ml of methylene chlorideand 80 ml (1 mol) of 4 allyl chloride was exposed for 20 minutes, whilerefluxing, to light from an Osram Vitalux incandescent lamp 4.5 X 10rad/h. Subsequently, the reaction mixture was subjected to fractionateddistillation in vacuo. 73.5 g 89.5 percent of the theory) of pure (B-bromoisopropyl)-isocyanate were obtained.

EXAMPLE48 EXAMPLE49 0.1 MOI of crude N-bromo-3,4-dimethylazetidinone-(2)and 33.5 g (0.6 mol) of isobutylene were mixed at 69 C and the mixturewas cooled to l93 C by means of liquid nitrogen. This cooled mixture wasirradiated for 6 hours at a dose rate of 2.2 X 10 rad/h in the mannerdisclosed in Example 46. Subsequently, the isobutylene was evaporated at-55 to -60 C within 6 minutes at greatly reduced pressure. The solidresidue was then dissolved in methylene chloride at 25 C and an infraredspectrum of the solution was taken. With the aid of the infraredspectrum an isocyanate proportion of from to 8 percent could beevaluated in the irradiated substance by means of comparative mixtures.

The following examples 50 to 70 are compiled in the Table. The reactionmixtures were worked up in the manner disclosed hereinbefore byfractionated distillation in vacuo. ln examples 52, 53, 55, 60 and 66the low-boiling proportions of the reaction mixture were evaporatedunder greatly reduced pressure at a temperature below -5 C.

We claim:

l. A process for the preparation of a compound of the formula in which Xis bromine or chlorine, R and R are hydrogen, chlorine or lower alkyl, Ris hydrogen or lower alkyl and R is hydrogen, alkyl, haloalkyl oralkenyl of each one to 22 carbon atoms or cycloalkyl of four to eightcarbon atoms, an aromatic radical of the benzene series, lower acyloxy,lower carbo-alkoxy,or if one or both of the radicals R and R stand forchlorine lower alkoxy, or each two of the radicals R, R, R and Rtogether form a cycloaliphatic ring or ring system of each 4 to ringmembers, which comprises contacting a compound of the formula in whichX, R, R R and R are as defined above, with a member selected from thegroup consisting of an olefin or an acetylene at a temperature of about200" C to about +250 C in the absence of a compound being capable offorming thermally free radicals in this temperature range.

2. The process as claimed in claim 1, wherein X is bromine.

3. The process as claimed in claim 1, wherein R is hydrogen, alkyl,haloalkyl or alkenyl of each up to 10 carbon atoms, or cyclyalkyl offive to eight carbon atoms, phenyl, acyloxy of a lower alkane carboxylicacid, lower carboalkoxy or if one or both of the radicals R and R standfor chlorine lower alkoxy.

4. The process as claimed in claim 1, wherein two of the radicals R, R Rand R together are alkylene of three to six carbon atoms or a bivalentcycloalkyl or cycloalkenyl hydrocarbon radical of each 5 to 8 carbonatoms.

5. The process as claimed in claim 1, wherein the olefin or acetylene isan alkene, alkadiene, haloalkene, alkenylester, alkenylether,cycloalkene or an unsaturated phenyl aliphatic hydrocarbon of up toeight carbon atoms each.

6. The process as claimed in claim 1, wherein the olefin or acetylene isan alkene, alkadiene, alkyne, cyclo-alkene, vinylbenzene,ethinylbenzene, haloalkene, vinylester or vinyl ether boiling undernormal pressure below 150 C.

7. The process as claimed in claim 1, wherein a solvent being inerttowards the isocyanate group is used.

8. The process as claimed in claim 1, wherein an aprotic solvent isused.

9. The process as claimed in claim 1, wherein a lower haloalkane is usedas solvent.

10. The process as claimed in claim 1, wherein a pure enantiomer of anasymmetric N-halogeno-B-lactam, in which at least R" and R aredifferent, is rearranged to an optically active B-halogenoalkylisocyanate.

11. The process as claimed in claim 1, wherein about 0.6 to about 8parts by weight, referred to N-halogeno- B-lactam, of an olefin or anacetylene boiling between about 30 and about C is heated with the N-halogeno-B-lactam for about 0.3 to about 3 hours to a' temperature ofabout 30 to about 100 C.

12. The process as claimed in claim 1, wherein the reaction is performedunder irradiation with light of a wavelength below about 700 nm.

13. The process as claimed in claim 1, wherein the reaction is performedunder irradiation with rays rich in energy of a radioactive radiator.

14. The process as claim in claim 1, wherein the reaction is performedunder irradiation with gamma rays.

* III I

1. A process for the preparation of a compound of the formula in which Xis bromine or chlorine, R1 and R2 are hydrogen, chlorine or lower alkyl,R3 is hydrogen or lower alkyl and R4 is hydrogen, alkyl, haloalkyl oralkenyl of each one to 22 carbon atoms or cycloalkyl of four to eightcarbon atoms, an aromatic radical of the benzene series, lower acyloxy,lower carbo-alkoxy, or - if one or both of the radicals R1 and R2 standfor chlorine - lower alkoxy, or each two of the radicals R1, R2, R3 andR4 together form a cycloaliphatic ring or ring system of each 4 to 10ring members, which comprises contacting a compound of the formula inwhich X, R1, R2, R3 and R4 are as defined above, with a member selectedfrom the group consisting of an olefin or an acetylene at a temperatureof about -200* C to about +250* C in the absence of a compound beingcapable of forming thermally free radicals in this temperature range. 2.The process as claimed in claim 1, wherein X is bromine.
 3. The processas claimed in claim 1, wherein R4 is hydrogen, alkyl, haloalkyl oralkenyl of each up to 10 carbon atoms, or cyclyalkyl of five to eightcarbon atoms, phenyl, acyloxy of a lower alkane carboxylic acid, lowercarboalkoxy or - if one or both of the radicals R1 and R2 stand forchlorine - lower alkoxy.
 4. The process as claimed in claim 1, whereintwo of the radicals R1, R2, R3 and R4 together are alkylene of three tosix carbon atoms or a bivalent cycloalkyl or cycloalkenyl hydrocarbonradical of each 5 to 8 carbon atoms.
 5. The process as claimed in claIm1, wherein the olefin or acetylene is an alkene, alkadiene, haloalkene,alkenylester, alkenylether, cycloalkene or an unsaturated phenylaliphatic hydrocarbon of up to eight carbon atoms each.
 6. The processas claimed in claim 1, wherein the olefin or acetylene is an alkene,alkadiene, alkyne, cyclo-alkene, vinylbenzene, ethinylbenzene,haloalkene, vinylester or vinyl ether boiling under normal pressurebelow 150* C.
 7. The process as claimed in claim 1, wherein a solventbeing inert towards the isocyanate group is used.
 8. The process asclaimed in claim 1, wherein an aprotic solvent is used.
 9. The processas claimed in claim 1, wherein a lower haloalkane is used as solvent.10. The process as claimed in claim 1, wherein a pure enantiomer of anasymmetric N-halogeno- Beta -lactam, in which at least R3 and R4 aredifferent, is rearranged to an optically active Beta -halogenoalkylisocyanate.
 11. The process as claimed in claim 1, wherein about 0.6 toabout 8 parts by weight, referred to N-halogeno- Beta -lactam, of anolefin or an acetylene boiling between about 30 and about 100* C isheated with the N-halogeno- Beta -lactam for about 0.3 to about 3 hoursto a temperature of about 30* to about 100* C.
 12. The process asclaimed in claim 1, wherein the reaction is performed under irradiationwith light of a wavelength below about 700 nm.
 13. The process asclaimed in claim 1, wherein the reaction is performed under irradiationwith rays rich in energy of a radioactive radiator.